Senior Software Engineer - Marketing Agent

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you’re a close but not exact match with the description, we hope you’ll still consider applying. Want to learn more about life at Klaviyo? Visit careers.klaviyo.com to see how we empower creators to own their own destiny.

Why You Should Join the Marketing Agent Team:

Klaviyo’s Marketing Agent team is building the next generation of intelligent tools that help businesses craft and execute powerful, personalized marketing strategies with minimal effort. This is a fast-paced, high-visibility initiative and powered by state-of-the-art technology. You’ll be part of a team creating products that support Klaviyo’s customers in driving key business outcomes through automated strategy generation.

As a Senior Software Engineer on this team, you’ll focus on frontend development building dynamic, user-facing interfaces that simplify complex workflows. You’ll partner closely with design, product, and data teams to build highly interactive, intuitive frontend experiences while contributing across the full stack. You’ll help design, implement, and iterate on a new class of features that leverage AI, including LLMs and agentic workflows, to support marketing execution end-to-end.

How You Will Make a Difference:

• Design and build complex, interactive UIs for reviewing, editing, and launching AI-generated marketing strategies that leverage the Klaviyo platform.
  
  
• Collaborate with cross-functional partners to rapidly iterate and experiment with user experiences.
  
  
• Lead implementation of end-to-end features, ensuring high-quality, performant frontend and backend systems.
  
  
• Drive project execution, contribute to technical design discussions, and own meaningful portions of the platform.
  
  
• Integrate AI tooling where appropriate, helping to shape Klaviyo’s AI product direction.

Who You Are:

• Experienced full stack engineer with a frontend emphasis—proficient in React, TypeScript, and modern state management libraries (e.g., Redux, Zustand).
  
  
• Skilled in backend development using Python, with knowledge of API design and cloud environments (preferably AWS).
  
  
• Strong communicator and collaborator with a track record of cross-functional leadership and system design.
  
  
• Comfortable working autonomously, navigating ambiguity, and delivering high-quality results in fast-paced settings.
  
  
• (Nice to have) Familiar with AI production environments and tools such as LangChain, vector databases, and retrieval-augmented generation.

Technologies We Use:

• React, TypeScript, Zustand, Redux
• Python, API frameworks
• AWS, modern cloud services
• LLM tools and libraries (LangChain, vector DBs, etc.)

We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025.

Please see the independent bias audit report covering our use of Covey here

Massachusetts Applicants:
It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant’s job-related skills, relevant experience, education or training, and work location.

In addition to base salary, our total compensation package may include participation in the company’s annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility. Please visit Klaviyo Rewards to find out more about our Total Rewards package.

Your recruiter can provide more details about the specific salary/OTE range for your preferred location du